Congestive heart failure (CHF) remains one of the most costly diseases in the industrialized world, both in terms of healthcare dollars and the loss of human life. Despite great strides made in the treatment of CHF using mechanical ventricular assist devices (VADs), several longstanding difficulties associated with pumping blood continue to limit their long-term use. Among the most troublesome have been the increased risk of infection associated with the use of percutaneous drivelines and the persistent risk of clot formation at the blood-device interface. Development of a completely self-contained, non-blood-contacting VAD for long-term use would therefore be an important advance in circulatory support technology. Toward that end, we have developed a muscle-powered co-pulsation VAD (Figure 1) that avoids both these problems by using an internal muscle energy converter (MEC) to drive a non-blood-contacting direct cardiac compression sleeve (DCCS) for long-term circulatory support.

Many natural organisms, such as fungal hyphae and plant roots, grow at their tips, enabling the generation of complex bodies composed of natural materials as well as dexterous movement and exploration. Tip growth presents an exemplary process by which materials synthesis and actuation are coupled, providing a blueprint for how growth could be realized in a synthetic system. Herein, we identify three underlying principles essential to tip-based growth of biological organisms: a fluid pressure driving force, localized polymerization for generating structure, and fluid-mediated transport of constituent materials. In this work, these evolved features inspire a synthetic materials growth process called extrusion by self-lubricated interface photopolymerization (E-SLIP), which can continuously fabricate solid profiled polymer parts with tunable mechanical properties from liquid precursors. To demonstrate the utility of E-SLIP, we create a tip-growing soft robot, outline its fundamental governing principles, and highlight its capabilities for growth at speeds up to 12 cm/min and lengths up to 1.5 m. This growing soft robot is capable of executing a range of tasks, including exploration, burrowing, and traversing tortuous paths, which highlight the potential for synthetic growth as a platform for on-demand manufacturing of infrastructure, exploration, and sensing in a variety of environments.

Direct cardiac compression (DCC) holds enormous potential as a safe and effective means to treat heart failure patients who require long-term, or even permanent, biventricular support. However, devices developed to date are not tuned to meet the individual compression requirements of the left and right ventricles, which can differ substantially. In this paper, a systematic study examining the relationship, range, and effect of independent pressures on the left and right epicardial surfaces of a passive human heart model was performed as a means to optimize cardiac output via DCC support. Hemodynamic and tissue deformation effects produced by varying epicardial compressions were examined using finite element analysis. Results indicate that 1) designing a direct cardiac compression pump that applies separate pressures to the left and right ventricles is critical to maintain equivalent stroke volume for both ventricles, and 2) left and right ventricular epicardial pressures of 340 mmHg and 44 mmHg, respectively, are required to induce normal ejection fractions in a passive heart. This pilot study provides fundamental insights and guidance towards the design of improved direct cardiac compression devices for long-term circulatory support.

With medical institutions increasing the use of medical simulators for educational purposes it is detrimental that the knowledge gap regarding tissue mechanical properties be researched further in depth. The grasper device discussed throughout this paper aims to provide researchers a handheld device capable of testing soft organs and tissue in-vivo and ex-situ in a laboratory setting. The device consists of two load cells on the inner jaws of the grasper to measure compressive force and an encoder to monitor the graspers angular position which yields tissue position and strain. Accompanying the grasper is a GUI written in Rust which is capable of data file management, and providing a 10 second live feed of load cell and encoder readings. The grasper device is currently being employed in a study testing the tissue mechanical response of porcine tissue at states ranging from in-vivo to ex-situ post freeze. The results from this test, and subsequent tests using the grasper have the capability of providing much needed knowledge regarding tissue mechanical properties to improve medical simulators and medical education as a whole.

Peripheral artery disease (PAD) results from atherosclerotic plaque deposition on arterial walls causing reduced blood flow to affected tissue and can result in pain, tissue loss, poor wound healing, limb loss, and death. Diagnosis of PAD and clinical assessment of these patients requires the use of a vascular Doppler device. By emitting an ultrasound signal when placed over an artery and measuring the Doppler shift of the signal reflected from moving blood cells, this device produces an audio output descriptive of several blood flow parameters. As shown through multiple rounds of clinician interviews, current vascular Dopplers are expensive, bulky, and lack objective signal analysis. An improved vascular Doppler offering solutions to these problems was designed and prototyped. This prototype demonstrated a reduction in cost and comparable signal quality compared to Doppler devices currently available, and offered an opportunity for future development of automated signal analysis capabilities.